UXML element TreeView

C# class: TreeView
Namespace: UnityEngine.UIElements
Base class: BaseTreeView

Inherited attributes

This element inherits the following attributes from its base class:

名称	类型	描述
`auto-expand`	`boolean`	When true, items are automatically expanded when added to the TreeView.
`binding-path`	`string`	Path of the target property to be bound.
`fixed-item-height`	`int`	The height of a single item in the list, in pixels. This property must be set when using the `virtualizationMethod` is set to `FixedHeight`, for the collection view to function.
`focusable`	`boolean`	True if the element can be focused.
`reorderable`	`boolean`	Gets or sets a value that indicates whether the user can drag list items to reorder them. The default values is `false`. Set this value to `true` to allow the user to drag and drop the items in the list. The collection view provides a default controller to allow standard behavior. It also automatically handles reordering the items in the data source.
`selection-type`	`UIElements.SelectionType`	Controls the selection type. The default value is `SelectionType.Single`. When you set the collection view to disable selections, any current selection is cleared.
`show-alternating-row-backgrounds`	`UIElements.AlternatingRowBackground`	This property controls whether the background colors of collection view rows alternate. Takes a value from the `AlternatingRowBackground` enum.
`show-border`	`boolean`	Enable this property to display a border around the collection view. If set to true, a border appears around the ScrollView that the collection view uses internally.
`tabindex`	`int`	An integer used to sort focusables in the focus ring. Must be greater than or equal to zero.
`virtualization-method`	`UIElements.CollectionVirtualizationMethod`	The virtualization method to use for this collection when a scroll bar is visible. Takes a value from the `CollectionVirtualizationMethod` enum. The default values is `FixedHeight`. When using fixed height, you need to specify the `fixedItemHeight` property. Fixed height is more performant but offers less flexibility on content. When using `DynamicHeight`, the collection will wait for the actual height to be computed. Dynamic height is more flexible but less performant.

This element also inherits the following attributes from VisualElement:

名称	类型	描述
`content-container`	`string`	child elements are added to this element, usually this
`name`	`string`	The name of this VisualElement. Use this property to write USS selectors that target a specific element. The standard practice is to give an element a unique name.
`picking-mode`	`UIElements.PickingMode`	Determines if this element can be pick during mouseEvents or `IPanel.Pick` queries.
`style`	`string`	Reference to the style object of this element. Contains data computed from USS files or inline styles written to this object in C#.
`tooltip`	`string`	Text to display inside an information box after the user hovers the element for a small amount of time.
`usage-hints`	`UIElements.UsageHints`	A combination of hint values that specify high-level intended usage patterns for the `VisualElement`. This property can only be set when the `VisualElement` is not yet part of a `Panel`. Once part of a `Panel`, this property becomes effectively read-only, and attempts to change it will throw an exception. The specification of proper `UsageHints` drives the system to make better decisions on how to process or accelerate certain operations based on the anticipated usage pattern. Note that those hints do not affect behavioral or visual results, but only affect the overall performance of the panel and the elements within. It’s advised to always consider specifying the proper `UsageHints`, but keep in mind that some `UsageHints` might be internally ignored under certain conditions (e.g. due to hardware limitations on the target platform).
`view-data-key`	`string`	Used for view data persistence (ie. tree expanded states, scroll position, zoom level). This is the key used to save/load the view data from the view data store. Not setting this key will disable persistence for this `VisualElement`.

USS classes

The following table lists all the C# public property names and their related USS selector.

C# property	USS selector	描述
`ussClassName`	`.unity-tree-view`	The USS class name for TreeView elements. Unity adds this USS class to every instance of the TreeView element. Any styling applied to this class affects every TreeView located beside, or below the stylesheet in the visual tree.
`itemUssClassName`	`.unity-tree-view__item`	The USS class name for TreeView item elements. Unity adds this USS class to every item element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree.
`itemToggleUssClassName`	`.unity-tree-view__item-toggle`	The USS class name for TreeView item toggle elements. Unity adds this USS class to every item toggle element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree.
`itemIndentsContainerUssClassName`	`.unity-tree-view__item-indents`	The USS class name for TreeView indent container elements. Unity adds this USS class to every indent container element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree.
`itemIndentUssClassName`	`.unity-tree-view__item-indent`	The USS class name for TreeView indent elements. Unity adds this USS class to every indent element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree.
`itemContentContainerUssClassName`	`.unity-tree-view__item-content`	The USS class name for TreeView item container elements. Unity adds this USS class to every item container element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree.
`ussClassName`	`.unity-collection-view`	The USS class name for BaseVerticalCollectionView elements. Unity adds this USS class to every instance of the BaseVerticalCollectionView element. Any styling applied to this class affects every BaseVerticalCollectionView located beside, or below the stylesheet in the visual tree.
`borderUssClassName`	`.unity-collection-view--with-border`	The USS class name for BaseVerticalCollectionView elements with a border. Unity adds this USS class to an instance of the BaseVerticalCollectionView element if the instance’s `BaseVerticalCollectionView.showBorder` property is set to true. Any styling applied to this class affects every such BaseVerticalCollectionView located beside, or below the stylesheet in the visual tree.
`itemUssClassName`	`.unity-collection-view__item`	The USS class name of item elements in BaseVerticalCollectionView elements. Unity adds this USS class to every item element the BaseVerticalCollectionView contains. Any styling applied to this class affects every item element located beside, or below the stylesheet in the visual tree.
`dragHoverBarUssClassName`	`.unity-collection-view__drag-hover-bar`	The USS class name of the drag hover bar. Unity adds this USS class to the bar that appears when an item element is dragged. The `BaseVerticalCollectionView.reorderable` property must be true in order for items to be dragged. Any styling applied to this class affects every BaseVerticalCollectionView located beside, or below the stylesheet in the visual tree.
`itemDragHoverUssClassName`	`.unity-collection-view__item--drag-hover`	The USS class name applied to an item element on drag hover. Unity adds this USS class to the list element that is dragged. The `BaseVerticalCollectionView.reorderable` property must be set to true for items to be draggable. Any styling applied to this class affects every BaseVerticalCollectionView item located beside, or below the stylesheet in the visual tree.
`itemSelectedVariantUssClassName`	`.unity-collection-view__item--selected`	The USS class name of selected item elements in the BaseVerticalCollectionView. Unity adds this USS class to every selected element in the BaseVerticalCollectionView. The `BaseVerticalCollectionView.selectionType` property decides if zero, one, or more elements can be selected. Any styling applied to this class affects every BaseVerticalCollectionView item located beside, or below the stylesheet in the visual tree.
`itemAlternativeBackgroundUssClassName`	`.unity-collection-view__item--alternative-background`	The USS class name for odd rows in the BaseVerticalCollectionView. Unity adds this USS class to every odd-numbered item in the BaseVerticalCollectionView when the `BaseVerticalCollectionView.showAlternatingRowBackground` property is set to `ContentOnly` or `All`. When the `showAlternatingRowBackground` property is set to either of those values, odd-numbered items are displayed with a different background color than even-numbered items. This USS class is used to differentiate odd-numbered items from even-numbered items. When the `showAlternatingRowBackground` property is set to `None`, the USS class is not added, and any styling or behavior that relies on it’s invalidated.
`listScrollViewUssClassName`	`.unity-collection-view__scroll-view`	The USS class name of the scroll view in the BaseVerticalCollectionView. Unity adds this USS class to the BaseVerticalCollectionView’s scroll view. Any styling applied to this class affects every BaseVerticalCollectionView scroll view located beside, or below the stylesheet in the visual tree.
`disabledUssClassName`	`.unity-disabled`	USS class name of local disabled elements.

UXML element ToolbarToggle

UXML element TwoPaneSplitView

手册

UXML element TreeView

Inherited attributes

USS classes